Flavonoid glycosides of the black locust tree, Robinia pseudoacacia (Leguminosae)

The 7-O-β-d-glucuronopyranosyl-(1 → 2)[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranosides of luteolin (1), apigenin (2), diosmetin (3), and acacetin (8) were isolated from leaves of Robinia pseudoacacia together with two known acacetin triglycosides. Comparative analysis of leaf and flower extracts by LC-UV and LC-MS highlighted a divergence in flavonoid chemistry between flavone 7-O-glycosides and flavonol 3,7-di-O-glycosides, respectively, and differences in glycosylation profiles.